Animals by classes

Warm-blooded animals with hair or fur that feed their young on milk.

Feathered, egg-laying animals with wings, most of which can fly.

Turtles, crocodilians, lizards, snakes and their extinct relatives.

Frogs, salamanders and caecilians that start life in water.

Gilled animals that live in water, from clownfish to whale sharks.

Six-legged animals with a three-part body, the largest group on Earth.

Eight-legged animals: spiders, scorpions, ticks and mites.

Soft-bodied animals such as octopuses, snails and clams.

Crabs, lobsters, shrimp and their hard-shelled relatives.

Cnidarians including true jellyfish, box jellyfish and hydrozoans.

Tentacled marine cnidarians, including reef-building corals and sea anemones.

Soft-bodied invertebrates including annelids, flatworms and roundworms.

Many-legged arthropods with one pair of legs on each trunk segment.

Segmented arthropods with two pairs of legs on most body segments.

Spiny marine echinoderms with a rigid internal skeleton.

Marine echinoderms with arms surrounding a central disc.

Marine echinoderms that gather food with branching arms.

Marine chordates including sea squirts and free-swimming salps.

Marine chelicerates related to arachnids, despite their common name.

Marine arthropods of the class Pycnogonida with slender bodies and long legs.

Extinct members of the evolutionary lineage that also includes mammals.

Extinct invertebrates and ancient organisms whose placement remains debated.

Gelatinous marine invertebrates of the phylum Ctenophora.

Aquatic filter-feeding animals of the phylum Porifera.

Marine echinoderms with slender, flexible arms and a distinct central disc.

Marine echinoderms with elongated bodies and feeding tentacles around the mouth.

Microscopic eight-legged animals also known as water bears.

Plants, microorganisms and microbial structures included in the reference index; these are not animals.